Fails to compile with XeLaTeX in TL2015 when including `newtxmath`

All my LaTeX documents stopped compiling with XeLaTeX from TeX Live 2015 sometime in the last two months. It was working before. Here is a minimum working example:

documentclass[11pt]{scrartcl}

usepackage{libertine}
usepackage[libertine]{newtxmath}

% DeclareSymbolFont{operators}{encodingdefault}{familydefault}{m}{n}

begin{document}
end{document}

Trying to compile like this: xelatex -interaction nonstopmode bug, gives me the following error:

(/opt/texlive/2015/texmf-dist/tex/generic/kastrup/binhex.tex)
tx@Isdigit=count137
)
! Incomplete iftrue; all text was ignored after line 128.
<inserted text> 
                fi 
l.5 

The file ended while I was skipping conditional text.
This kind of error happens when you say `if...' and forget
the matching `fi'. I've inserted a `fi'; this might work.

)
! Incomplete iftrue; all text was ignored after line 128.
<inserted text> 
                fi 
<*> bug

The file ended while I was skipping conditional text.
This kind of error happens when you say `if...' and forget
the matching `fi'. I've inserted a `fi'; this might work.

! Emergency stop.
<*> bug

*** (job aborted, no legal end found)

What is going wrong? I have tried the suggestion in this answer with no luck.